Lighting system with cooling arrangement

Abstract

The invention provides a lighting system ( 100, 200, 300 ) for controlling the growth of plants, the system comprising; an array of solid state/semiconductor light sources ( 101, 201, 301 ) adapted to emit light of a predetermined wavelength or wavelength range; and a cooling arrangement( 102, 202, 302 ) comprising a pipe ( 103, 203, 303 ) having at least one inlet opening for receiving a gaseous cooling medium and a plurality of outlet openings ( 105, 205, 305 ) for releasing said gaseous cooling medium from said cooling arrangement, the cooling arrangement being in mechanical and thermal contact with said light sources. The invention also provides a method for controlling the growth of a plant in a greenhouse of growth chamber. The invention allows promoting the photosynthesis of a plant by modifying the conditions (light intensity, temperature, CO 2 concentration) locally around the plant.

The invention claimed is: 
     
       1. A lighting system for controlling the growth of plants, the system comprising:
 an array of solid state light sources adapted to emit visible light of a predetermined wavelength or wavelength range from 400 nm to 800 nm; 
 a cooling arrangement comprising a pipe for conducting a cooling medium, the pipe having at least one inlet opening for receiving a gaseous cooling medium and a plurality of outlet openings for releasing said gaseous cooling medium from said cooling arrangement, the cooling arrangement being in mechanical and thermal contact with said light sources, wherein said array of solid state light sources is arranged only on the outside of said pipe, wherein the cooling arrangement is connectable to a CO 2  source and configured to allow CO 2  to be released through the plurality of outlet openings, and wherein said solid state light sources and said plurality of outlet openings are configured to modify light intensity, temperature, and CO 2  concentration locally around said plants and further configured to promote photosynthesis of said plants. 
 
     
     
       2. A lighting system according to  claim 1 , wherein said pipe is thermally conductive. 
     
     
       3. A lighting system according to  claim 1 , wherein said outlet openings are closable. 
     
     
       4. A lighting system according to  claim 3 , wherein the openings are variably closable so that the size of the outlet openings is adjustable. 
     
     
       5. A lighting system according to  claim 1 , wherein the cooling arrangement forms an open system. 
     
     
       6. A lighting system according to  claim 1 , wherein at least part of said pipe is in thermal connection with said light sources. 
     
     
       7. A lighting system according to  claim 1 , wherein said outlet openings are located on the same side of the pipe as the light sources. 
     
     
       8. A lighting system according to  claim 1 , further comprising one or more of the following devices and monitors: a closure control device for controlling the size of the outlet openings; a light output control device; a temperature monitor; a CO 2  content monitor; and a clock or a timer. 
     
     
       9. A method of controlling the growth of a plant in a greenhouse or growth chamber, comprising steps of:
 providing a lighting system, comprising an array of solid state light sources adapted to emit visible light of a predetermined wavelength or wavelength range from 400 nm to 800 nm and a cooling arrangement comprising pipe for conducting a cooling medium, the pipe having at least one inlet opening for receiving a gaseous cooling medium and a plurality of outlet openings for releasing said gaseous cooling medium from said cooling arrangement, the cooling arrangement being a mechanical and thermal contact with said light source, wherein said array of solid state light sources is arranged only on the outside of said pipe, wherein said array of light sources and said plurality of outlet openings are located in the interior of the greenhouse or growth chamber, and wherein said solid state light sources and said plurality of outlet openings are configured to modify light intensity, temperature, and CO 2  concentration locally around said plant and further configured to promote photosynthesis of said plant; 
 introducing a cooling medium containing CO 2  into the pipe via the at least one inlet opening; 
 conducting said cooling medium containing CO 2  through the pipe such that the cooling medium may absorb heat generated by said array of light sources; and 
 allowing said cooling medium containing CO 2  to escape from the cooling arrangement via one or more of the outlet openings into the greenhouse or growth chamber. 
 
     
     
       10. A method according to  claim 9 , wherein at least one of said light sources and at least one of said plurality of outlet openings both are located in the vicinity of a plant whose growth is to be controlled. 
     
     
       11. A method according to  claim 9 , wherein said cooling medium is ambient air collected from outside the greenhouse or growth chamber. 
     
     
       12. A method according to  claim 11 , comprising the step of supplementing the cooling medium with CO 2  before it is allowed to escape from the cooling arrangement into the greenhouse or growth chamber. 
     
     
       13. A method according to  claim 9 , wherein the cooling medium has a CO 2  content of at least 500 ppm.